Portions of the Amazon rainforest are now emitting more carbon dioxide than they absorb — a troubling sign for the fight against climate change, a new study suggests.
Deforestation and an accelerating warming trend have contributed to the change in the carbon balance, which is most severe in the southeastern region of the Amazon, where there are rising temperatures and reduced rainfall in the dry season. The most affected regions have warmed by 4.5 degrees Fahrenheit during the dry season in the past 40 years, comparable to the changes seen in the rapidly warming Arctic.
The Amazon region, home to the planet’s largest tropical forests, has served as an important absorber of carbon dioxide. Changing weather patterns have reduced its effectiveness as a buffer for climate change, and the conditions may be pushed even more by global warming, with still more carbon dioxide being released.
“This is a negative loop,” said Luciana Vanni Gatti, a scientist at Brazil’s National Institute for Space Research and an author of the study, which was published Wednesday in the journal Nature.
In recent years, a growing number of studies have suggested the region’s ability to remove carbon from the air and store it so it will not contribute to rising global temperatures is being degraded.
The research published Wednesday included measurements of carbon dioxide and carbon monoxide levels taken from small planes during about 600 flights from 2010 to 2018. The pilots flew to altitudes of a few miles above the tree canopy then descended and took repeated measurements in the vertical column of air. The results showed the greatest changes to the ecological balance in areas that had suffered large-scale deforestation and had been burned heavily to dispose of dead trees and to clear land, Gatti said.
Thomas Lovejoy of George Mason University said there is hope for restoring balance, at least to a degree.
“The ability to build back a margin of safety” through reforestation is very real, he said.
Any changes may be long in coming and will face political opposition. President Jair Bolsonaro of Brazil has overseen skyrocketing deforestation in the Amazon.
— © The New York Times Co.